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<h2><a href="closure_goog_storage_mechanism_mechanismfactory.js.html">mechanismfactory.js</a></h2>

<pre class="prettyprint lang-js">
<a name="line1"></a>// Copyright 2011 The Closure Library Authors. All Rights Reserved.
<a name="line2"></a>//
<a name="line3"></a>// Licensed under the Apache License, Version 2.0 (the &quot;License&quot;);
<a name="line4"></a>// you may not use this file except in compliance with the License.
<a name="line5"></a>// You may obtain a copy of the License at
<a name="line6"></a>//
<a name="line7"></a>//      http://www.apache.org/licenses/LICENSE-2.0
<a name="line8"></a>//
<a name="line9"></a>// Unless required by applicable law or agreed to in writing, software
<a name="line10"></a>// distributed under the License is distributed on an &quot;AS-IS&quot; BASIS,
<a name="line11"></a>// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
<a name="line12"></a>// See the License for the specific language governing permissions and
<a name="line13"></a>// limitations under the License.
<a name="line14"></a>
<a name="line15"></a>/**
<a name="line16"></a> * @fileoverview Provides factory methods for selecting the best storage
<a name="line17"></a> * mechanism, depending on availability and needs.
<a name="line18"></a> *
<a name="line19"></a> */
<a name="line20"></a>
<a name="line21"></a>goog.provide(&#39;goog.storage.mechanism.mechanismfactory&#39;);
<a name="line22"></a>
<a name="line23"></a>goog.require(&#39;goog.storage.mechanism.HTML5LocalStorage&#39;);
<a name="line24"></a>goog.require(&#39;goog.storage.mechanism.HTML5SessionStorage&#39;);
<a name="line25"></a>goog.require(&#39;goog.storage.mechanism.IEUserData&#39;);
<a name="line26"></a>goog.require(&#39;goog.storage.mechanism.IterableMechanism&#39;);
<a name="line27"></a>goog.require(&#39;goog.storage.mechanism.PrefixedMechanism&#39;);
<a name="line28"></a>
<a name="line29"></a>
<a name="line30"></a>/**
<a name="line31"></a> * The key to shared userData storage.
<a name="line32"></a> * @type {string}
<a name="line33"></a> */
<a name="line34"></a>goog.storage.mechanism.mechanismfactory.USER_DATA_SHARED_KEY =
<a name="line35"></a>    &#39;UserDataSharedStore&#39;;
<a name="line36"></a>
<a name="line37"></a>
<a name="line38"></a>/**
<a name="line39"></a> * Returns the best local storage mechanism, or null if unavailable.
<a name="line40"></a> * Local storage means that the database is placed on user&#39;s computer.
<a name="line41"></a> * The key-value database is normally shared between all the code paths
<a name="line42"></a> * that request it, so using an optional namespace is recommended. This
<a name="line43"></a> * provides separation and makes key collisions unlikely.
<a name="line44"></a> *
<a name="line45"></a> * @param {string=} opt_namespace Restricts the visibility to given namespace.
<a name="line46"></a> * @return {goog.storage.mechanism.IterableMechanism} Created mechanism or null.
<a name="line47"></a> */
<a name="line48"></a>goog.storage.mechanism.mechanismfactory.create = function(opt_namespace) {
<a name="line49"></a>  return goog.storage.mechanism.mechanismfactory.createHTML5LocalStorage(
<a name="line50"></a>      opt_namespace) ||
<a name="line51"></a>      goog.storage.mechanism.mechanismfactory.createIEUserData(opt_namespace);
<a name="line52"></a>};
<a name="line53"></a>
<a name="line54"></a>
<a name="line55"></a>/**
<a name="line56"></a> * Returns an HTML5 local storage mechanism, or null if unavailable.
<a name="line57"></a> * Since the HTML5 local storage does not support namespaces natively,
<a name="line58"></a> * and the key-value database is shared between all the code paths
<a name="line59"></a> * that request it, it is recommended that an optional namespace is
<a name="line60"></a> * used to provide key separation employing a prefix.
<a name="line61"></a> *
<a name="line62"></a> * @param {string=} opt_namespace Restricts the visibility to given namespace.
<a name="line63"></a> * @return {goog.storage.mechanism.IterableMechanism} Created mechanism or null.
<a name="line64"></a> */
<a name="line65"></a>goog.storage.mechanism.mechanismfactory.createHTML5LocalStorage = function(
<a name="line66"></a>    opt_namespace) {
<a name="line67"></a>  var storage = new goog.storage.mechanism.HTML5LocalStorage();
<a name="line68"></a>  if (storage.isAvailable()) {
<a name="line69"></a>    return opt_namespace ? new goog.storage.mechanism.PrefixedMechanism(
<a name="line70"></a>        storage, opt_namespace) : storage;
<a name="line71"></a>  }
<a name="line72"></a>  return null;
<a name="line73"></a>};
<a name="line74"></a>
<a name="line75"></a>
<a name="line76"></a>/**
<a name="line77"></a> * Returns an HTML5 session storage mechanism, or null if unavailable.
<a name="line78"></a> * Since the HTML5 session storage does not support namespaces natively,
<a name="line79"></a> * and the key-value database is shared between all the code paths
<a name="line80"></a> * that request it, it is recommended that an optional namespace is
<a name="line81"></a> * used to provide key separation employing a prefix.
<a name="line82"></a> *
<a name="line83"></a> * @param {string=} opt_namespace Restricts the visibility to given namespace.
<a name="line84"></a> * @return {goog.storage.mechanism.IterableMechanism} Created mechanism or null.
<a name="line85"></a> */
<a name="line86"></a>goog.storage.mechanism.mechanismfactory.createHTML5SessionStorage = function(
<a name="line87"></a>    opt_namespace) {
<a name="line88"></a>  var storage = new goog.storage.mechanism.HTML5SessionStorage();
<a name="line89"></a>  if (storage.isAvailable()) {
<a name="line90"></a>    return opt_namespace ? new goog.storage.mechanism.PrefixedMechanism(
<a name="line91"></a>        storage, opt_namespace) : storage;
<a name="line92"></a>  }
<a name="line93"></a>  return null;
<a name="line94"></a>};
<a name="line95"></a>
<a name="line96"></a>
<a name="line97"></a>/**
<a name="line98"></a> * Returns an IE userData local storage mechanism, or null if unavailable.
<a name="line99"></a> * Using an optional namespace is recommended to provide separation and
<a name="line100"></a> * avoid key collisions.
<a name="line101"></a> *
<a name="line102"></a> * @param {string=} opt_namespace Restricts the visibility to given namespace.
<a name="line103"></a> * @return {goog.storage.mechanism.IterableMechanism} Created mechanism or null.
<a name="line104"></a> */
<a name="line105"></a>goog.storage.mechanism.mechanismfactory.createIEUserData = function(
<a name="line106"></a>    opt_namespace) {
<a name="line107"></a>  var storage = new goog.storage.mechanism.IEUserData(opt_namespace ||
<a name="line108"></a>      goog.storage.mechanism.mechanismfactory.USER_DATA_SHARED_KEY);
<a name="line109"></a>  if (storage.isAvailable()) {
<a name="line110"></a>    return storage;
<a name="line111"></a>  }
<a name="line112"></a>  return null;
<a name="line113"></a>};
</pre>


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